Not necessarily Traci, if there is no dipstick there will be two plugs on the gearbox, a drain plug and a level plug. To check the condition of the gearbox fluid undo the drain plug until the fluid starts to run out a bit ( catch this fluid in a container ) and check the condition of it. If it is no good then it will all have to be drained of. then replace the drain plug and remove the level plug and refill the gearbox through the hole until the new gearbox fluid starts to run out of the hole, replace the level plug and job done.